Security protocols such as IPSec (Internet Protocol Security), SSL/TLS (Secure sockets Layer/Transport Layer Security) and others use cryptographic functions that are both CPU and memory intensive.
To aggravate the problem, most commercial implementation of cryptographic functions only handle complete Packet Data Units (PDU)—meaning, the receiving end of a flow of cipher text must re-assemble the complete unit of data encrypted by the transmitting end. As a result, latency (which adds to response time) is incurred while the receiving end reconstructs the PDU.
This process, in turns, requires substantial memory for buffering and very significant CPU cycles for ordering fragments, complying with transmission protocol such as TCP and providing intricate buffer management.
As the Internet transforms into the virtual highway for day-to-day applications such as e-mail, e-banking and e-trading, security with minimal cost in performance is becoming a necessity.